04/16/2012

Surrogate nuclear reactions approach featured in Reviews of Modern Physics

Linda A Lucchetti, LLNL, (925) 422-5815, lucchetti1@llnl.gov



The idea of the surrogate approach is to replace the first step of the desired a+238U, that is experimentally easier to access yet populates the same compound nucleus, 238U.
Nuclear reaction cross sections are important for a variety of applications in the areas of astrophysics, nuclear energy, and national security.

When these cross sections cannot be measured directly or predicted reliably, it becomes necessary to develop indirect methods for determining the relevant reaction rates, such as the surrogate nuclear reactions approach. This work by Lab scientists is featured in a recent issue of the journal, Reviews of Modern Physics.

The new research is the culmination of a decade of experimental and theoretical effort by many researchers at LLNL to develop techniques for indirectly obtaining information on important nuclear reactions that cannot be measured directly.

Neutron-induced reactions play a crucial role in the formation of elements heavier than iron in the cosmos, can be used in newly designed nuclear reactors, and are crucial to understanding weapon performance for the stockpile stewardship mission.

The surrogate idea was first used in the 1970s to estimate cross sections for neutron-induced fission. Livermore's more recent efforts to refine and extend this approach for a wider range of reactions have resulted in world-wide interest in the technique, as well as strong collaborations between the LLNL researchers and nuclear scientists at many institutions (7 national laboratories and 6 universities in 5 countries). The method is expected to become an important focus of inverse-kinematics experiments at rare-isotope facilities, such as the Department of Energy's $550 million Facility for Rare Isotope Beams (FRIB), which will be the new national user facility for nuclear science.

LLNL scientists Jutta E. Escher, Jason T. Burke, Frank S. Dietrich, Nicholas D. Scielzo, Ian J. Thompson, and Walid Younes authored the paper upon invitation by the journal.




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